In single lens reflex cameras of the related art, a so-called dedicated phase difference sensor is mounted to realize fast autofocus. On the other hand, compact cameras, mirrorless cameras, and the like generally employ a contrast detection autofocus (hereinafter referred to as AF) system. In addition, in order to realize fast AF in such cameras, a method of embedding an image sensor for phase difference detection in another image sensor has been proposed (Patent Literature 1).
Furthermore, a method of mounting both a dedicated phase difference detecting module and a phase difference detecting image sensor has also been proposed in order to obtain advantages of both sensors using the above-described technique (Patent Literature 2).